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High Density Workholding Using New Serrated
Mounting Components Key To Quick Turnaround At JEM Technical
-- Kurt Cluster Tower FMS Provides Maximum Setup Versatility While Machining
Center Operates Non-Stop
Long Lake, Minnesota: Keeping the spindle turning in CNC machining centers
is said to be the key to success these days. For JEM Technical Marketing,
success means keeping the spindle turning 24 hours a day. With enhancements
to its high density workholding, JEM is able to double the parts it holds
in its Cluster Tower setups to keep its new machining center turning unattended
for an extra 7 hour shift in every 24 hour workday.
JEM Technical Marketing manufactures a broad line of custom manifold
assemblies used in all types of fluid power applications such as off-highway
vehicles, tractors and road graders. These manifolds are made from 6061
aluminum and are finish machined in a wide range of sizes and with numerous
SAE ports, valve cavities, and threaded holes, some with precision features
designed to handle various fluid power components.
 These
manifold assemblies are manufactured for large OEM applications but are
also available for limited application use. Part runs vary from just 1
to well over 3000 units with the required machining accuracies ranging
from .0005 to .001 inch. To achieve real production efficiency with this
diverse product mix, JEM Technical decided something had to be done with
its workholding to maximize productivity. (Photo One)
Photo One Caption: Manifold assemblies manufactured by
JEM Technical Marketing have dozens of precision machined holes located
on all sides of the manifold. High Density Kurt Workholding With Innovative
Serrated_Interlocking Of Modular Components Provides Solution
"Our precision manifold machining process is all about high density,"
says Peter Tackes, manufacturing manager for JEM Technical. "We've taken
a two station per face setup on the Kurt CarvLock cluster towers and gone
to four. That doubles the capacity of each tower setup. It allows our
operators to setup offline enough parts to run unattended through the
night." (Photo Two)
Photo Two Caption: Peter Tackes, JEM Technical Marketing,
has devised a workholding plan for maximum machine utilization and non-stop
operation while maintaining part setup versatility.
JEM Technical operates a new Mazak FH 4800 Palletech system which operates
at up to 12,000 rpm with a tool change time of 3.0 seconds (chip to chip).
The machine is used for a combination of milling, drilling, tapping and
boring operations. The system has a rapid traverse rate up to 1,968 ipm
in all axes and up to 30 horsepower in the spindle. Equipped with automatic
tool changer that carries 120 tools, the machine has an "X" travel of
22" (X), "Y" travel of 24" (Y), and "Z" travel of 22" (Z).
JEM Technical utilizes Kurt CarvLock cluster towers on its Palletech
system and just recently started using a new model with mating serrated
mounting surfaces. From a distance, it appears like those towers are the
ones that have been around for a number of years. But if you look more
closely, you'll see a new feature -- serrated mounting surfaces. These
new towers, called SeraLock™ have the usual four sides of the mounting
fixture. Each side of the pedestal features ductile iron mounting plates,
with two vertical T-slots. But they have something different and entirely
new -- the surface of these mounting plates is serrated. That is, the
surface is lined with V-shaped grooves and ridges. Upon inspection, these
grooves and ridges are plainly visible running across the plates.
What you can't see are the matching grooves and ridges on the mating
surfaces of the fixture blocks clamped to the mounting plates. The grooves
and ridges on these mating surfaces are precisely shaped and spaced so
that the match between the surfaces is very nearly perfect. When these
opposing grooves and ridges come together, they interlock, forming a very
rigid, very firm, and very level, highly repeatable interface. Matching
the grooves and ridges naturally and automatically aligns the surfaces,
making subsequent re-clampings highly repeatable. (Photos Three and Four)
Originally designed for two workholding stations per face, JEM Technical
sets up their SeraLock cluster towers with three and sometimes four workholding
stations per facing. "It all depends on the size of the part," says Tackes.
"If the part height is sufficiently narrow, we'll stack up to four parts
per facing. Alignment of three or four side-by-side parts would be difficult
to achieve using conventional cluster towers but not with the new Kurt
SeraLock setup." (Photo Five)
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Photo Five Caption: High density workholding to the
ultimate. JEM Technical Marketing's workholding setup also uses
Kurt's standard MoveLock module which are two-piece vises that position
and hold parts in the tower setup.
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Incorporating Kurt's MoveLock™ module, JEM Technical's SeraLock
workholding is an entirely new approach. The MoveLocks are simple, two-piece
vises which provide independent mounting of stationary and moveable elements
in the setup. What's different in this setup are the intermediate modules,
or the combination spacer/lockdown devices which are positioned between
each of the workholding stations.They have the dual function of aligning,
holding and locking down the parts to be machined. But it's all made possible
with the Kurt SeraLock mounting platform.
Interlocking Serrated Surfaces Enhances
The Modular Approach
Kurt manufactures its serrated surfaces in pallet or multi-sided tower
configurations for application on either vertical or horizontal machining
centers. JEM Technical Marketing's setup maximizes the workholding in
the space available on each mounting face. But the key to the system is
in the accuracy of the serrations, both in form and in spacing. The reasons
are obvious.
A firm, level and repeatable interface cannot be achieved if the serrations
on both the subplate and clamping element are not a perfect match. The
spacing, or pitch, of the serrations allows the use of a variety of economical,
short-stroke clamping elements. The moveable and stationary components
of the clamp can be located relative to one another on the sub-plate so
that the needed stroke of the moveable component need be little more than
the pitch of the serration. In the SeraLock system, a sixteen pitch (sixteen
serrations per inch) pattern is utilized. Thus, the stroke of the clamping
elements need not exceed .062" unless otherwise dictated by workpiece
configuration.
Different Clamping Elements Promote Workholding
Flexibility
Repeat setups are easy because the SeraLock serrations take care of location
and alignment of clamping elements. And because of the versatility inherent
in the system, setups ranging from extremely high-density loads of small
parts to single station configurations for very large workpieces can be
accommodated on the same workholding surface. JEM Technical Marketing's
part size and quantity requirements are the ideal candidate for this system.
The two clamping elements it employs are the Kurt MoveLock and MiniLock™.
Of the two, JEM utilizes the MoveLock most often because it is a precision
two-piece vise with a robust design. Actuated manually or hydraulically
(JEM opted for the manual style), these MoveLock clamping elements are
fitted with special jaw plates to adapt to the different workpiece configurations.
Tackes says that the system has helped triple output in its 9 man machining
department without adding more help. "We keep the machines running with
operator attention and setup through the end of the second shift. Toward
the end of that shift around 11 p.m., the operator carefully checks the
first run of parts. If all check out, and they usually do because we've
done our setup homework, they'll be machined to spec without operator
attention during the 11 to 6 shift.
"Most of the Ülights out' part runs are from just a single part to 100,"
Tackes said. "The machining is done at spindle speeds up to 12,000 rpm
with tolerances from .0005 to .001 inch. This process requires very skilled
operators who understand programming and managing the machines correctly.
The Kurt SeraLock towers have really made a difference in our productivity.
They help us improve our just-in-time response because with our product
lines, customers are constantly changing their requirements."
As for maintenance of the SeraLock mating serrations, Tackes said a little
simple house-cleaning as with any setup is all that's needed. "We have
a clean shop to start with and a clean shop policy. We keep the module's
serrations clean with a bronze brush."
Some additional benefits Tackes noted since adopting the Kurt SeraLock
Tower setup with the Mazak Palletech system include the need for less
machine floor space. Output has been tripled and three older machining
centers re-assigned to other uses, leaving room to add more offline loading
capability to the one machine or integrating a second machine into the
system.
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